I think that parents should have to sit a test or something before being allowed to care for a child. I know that we all do stupid things but there is stupid and then there is crazy stupid.
The thing is that Darwinism (evolution of those most able to adapt to the prevailing conditions) would see such people become extinct. Under that scenario the child of the stupid mother (who may have inherited some of her stupidity) would not have survived and so would not have procreated. End of the (stupid) line.